Skip to main content

Full text of "Text Book Of Mechanical Engineering"

See other formats


Strength of Fly Wheel Rim.

401

Fig-  353-    R is the  average radius (radius of gyration) of tHe
rotating flywheel rim, a hb.    If«/ = the weight of a cub, inch of

of

the material, w h is the weight of the darkly shaded solid, and
its centrifugal force,

But every such solid in the circumference acts radially as at A,
Fig. 351, and the flywheel tends to burst at ab^ as the boiler did
at//, Fig. 351.

. •. Centrifugal force per "I          .   ^  ,             f  safe strength

sq. in of rim       \* projected area = { gtrip ^^ ^

or

^                ,.

and  /tlbs. =

Istrip

2T**  2/lbsA

<   2   X   12 R         12

of
a b

then   ?7 = 1*64

A/

v

For cast iron, w == '26 andylbs= 1*25 x 2240

«\   Safe ^ = 1*64 /Y •^ixJli?= X70 ft pej. sec